Dynamo-electric machine.



O. A. PSILANDER & T. S. SCOTT.

DYNAMO ELECTRIC MAUHINE.

AIPLIOATION FILED 1 mm, 1906.

Patented May 3, 1910.

2 snnn'rs-snnn 'r 1.

WITNESS-ESL gzaaw G. A. PSILANDBR & T. S. SCOTT. DYNAMO ELECTRIC MAUHINE.

APPLICATION IILED F1116, 1906.

956,543. Patented May 3, 1910.

2 Mums-4mm 2 I IN ,ENTOR-S v WITNESSES Z a. ,Y I 6,6731% g gmwmm QATTORN'EY- ANDREW i. GRAHAM 001 PKDTO-UTHDGHAPNEIS. wAsMmaYON. O. C

UNITED STATES PA'r NT OFFICE.

WILLIAM HAY CALDWELL,.OF MALLAIG, SCOTLAND.

SENSiTIZED SURFACE OR FILM FOR PHOTOGRAPHIC PURPOSES.

956,567. it Drawing.

To all whom it may concern:

Be it known that I, WILLIAM HAY- Cannwnnn a subgect of the King of Great Britain and lrelan residin at Mallaig R. S. 0.,

6' Inverness-S hire Scot and, have invented Improvements in ensitiaed Surfacesor Films for Photographic Purposes, of which the following is a specification.

When light acts u on certain salts of silver% 10 for example the ha ogen' salts, a sub-salt 0 silver is believed to be produced with the formation of a free substance, such as chlorin, bromin or-iodin in the case of a halogen salt, but this action is at once arrested in the absence of an agent which will act as an absorbent of the substance set free.

The most active absorbents of chlorin, bromin or iodin are the so-called develop ing agentsused in the development of photographic images, but I'ha ve discovered the curious fact that most of these a cute, which are so active as to reduce the s' ver salts in the dark, are quite unable to render the same salts sensitive in the light by acting as 2 halogen absorbers. The reason for thisapparent paradox is thatin the light and in the presence of'the halogen acid formed by ;the halogen set free, the oxidized product of the reaction is itself again reduced with a second freeing of halogen which re-com bines with the sub-salt to' again form the 7 normal salt. Thus 2Ag Br.'-]- (3,H OH) +2Brr= 2A'g,l3r.-{-C,I;I +2H Br.= Mi'gBn-l-OgH, (HO) The product chinon (G ILOQ in the above equation is the oxidation ioduc't of many 0 the substances useddn evelcpmeiit. On

40 the other hand, substances which are not so easily oxidized as to be available for developing, are not sufliciently active as-absorbers.

bromin' and iodin :to enable them to act in such a' way as to render rapid silver films made with silver bromid .or silver iodid, sensitive. Thus, while the active developers which have amide (N11,)v and hydroxyl it) pd sa'.t1ons, "as for example hydroquino'nd-aiid 'pua-amidmphenoLare, for the reason given above, finite u bletoabsorb the free halogen res tingfrorn the actionof -l T 't'on a. silver ha-loid their isomeri,'s, with the same grou [sin the meta (1.8) p 1'tions,',as for-cxampe resorcin and meta-agip-phenol, able to absorb Specification 0'! Letters I'atent. r Application flied April 24, 1808. Serial No. 429,103.

sin lthe ortho v(l .2) or para- Patented May 3, 1910.

the halogen without reversion taking place, cannot do this sufficiently rapidly to form a v1s 1ble image in proper gradation.

At presnt sensitive surfaces containing sllver salts belong to one or other of -two classes, viz :-(l) in which the image formed by llght is not visible, or only very partially so, and requires to be, subsequently treated with a developer: (2) in which the image is obtained entirely by the action of light without the subsequent use of a developer.

Now the object of the present invention is and the consequent size of the particlesof silver salt aggregated into chemical contact; With such surfaces the exposure must so regulated that no more halogen will be set other vehicle present, in all cases a very limited amount. Further, at present in surfaces of the second class, the halogen set free under the action of light is absorbed by an organic salt of silver, as for example an acid silver citrate in the vehicle, with formation in this case of citric acid and the normal halogen salt of silver. .It is conceivable that a rapid surface might be made by the reduction of the silver salt than can be absorbed by the. gelatinor in this second class but hitherto this has-not been found possible. A developer sulficiently active to reduce the sub-salt of a silver haloidwould certainly. reduce the or-- nic silver salt in the dark, and if it be at my:

tempted transform the organicsalt, I vious to development, with a soluble be old salt, it is found that the minute quantity of sub-salt formed by, the action of light is destroyed .in the processyso far asits cal-pac ity for subsequent development is-concem'ed.

Further, even if itw'erepossible to develop. .only the ;organic-silv.er .salt tozform the? image, the want of stability of organic" compared with haloid silver salts would make process of little value.

properties are possessed by some salts or.

i hydrazin hereinbe a sulfurous acid salt of a hydrazin (RNH.NH,), such or instance as Now I have discovered that the organic An ideal substance for the purpose. mentioned should possess the following pro erties:--1. It should be incapablepf re uction in the light after its oxidation by the halogen set free. 7 2. It should not reduce, in the dark, the'silver salt employed, 3. It should absorb the halogen as rapidly as it is set free by light.

I have found that the above mentioned erivatives of hydrazin (NH NH and of hydroxylamin (NH,OH). For example, a sensitive surface having the above mentioned roperties can be prepared as follows :-In the preparation of the emulsion to form the sensitive surface, there ma be used, either one of the silver haloids a. one, or a mixture of two or more of them in the ordinary way. To the finished emulsion, when rapidity has been suitably adjusted by heat or otherwise, as in well known ways,

there is added the necessary amount of a suitable salt or compound of hydrazin, for example ahydrazin salt of an easily oxidizable acid such as phosphorous acid (H PO or sulfurous acid (H SO These salts can be made by adding a solutionof 1 the acid to hydrazin. hydrate (NH .NH ,HO), using methyl orange as an indicator of the completion ofKthe reaction.

Since chlorin, bromin and iodin form a series of silver salts of gradually'increasing' stability the compound of hydrazin -or hydroxylamin used in the preparation of the emulsion can be determined by a-consideration of such fact. For example in the case of silver chlorid, as the chlorin evolved by the action oflight is a gas that is, comparatively, easily absorbed, many of the compounds of hydrazin or hydroxylamin will be found suitable for use in the manufacture of sensitive surfaces for attaining the object. of this invention. For example, rimary fatty methyl hydrazin (GH,NH.NH,) may be used. With a halogen salt of greater stability, such as silver bromid, a more active compound of hydrazin or hydroxylamin is desirable than in the case of a chlorid, such for example. as the phosphorous acid salt of amount of the salt used in the preparation of'the emulsion is determined by a con sideration of the reducing action of the hydrazin, each molecule of hydrazin hydrate (NH,NH,HO), being ab e to reduce the ore referred to. The

sions in which the colloid vehicle is ether- I alcohol-collodion, it is necessar to. use a hydrazin salt or compound which is itself,

soluble in ether-alcohol, and of which some of the liydrazids, for instance formyl h drazin (HC()NH.NH,), are examples. rem emulsions thus prepared, sensitive-surfaces are then produced in the ordinary way.

Sensitivesurfaces embodying the mvention may also be produced bydip ing sensitive surfaces prepared in the ord mary way and consisting for example of surfaces or films mounted on glass, paper or. other supports or carriers, in a solution of a hydrazin or hydroxylamin salt or derivative. 7

Sensitiye surfaces produced 'as hereinbefore described can be exposed in the camera for any time longer than the shortest exposure necessar u to complete printin out or they an be exposed for a shor time and subsequently treated with a suitable developer, such as an alkaline developer, without previous treatment with an alkaline halogen. The developer should be such that it will act slowly or quickly accordin as the sensitive surface has been exposed or a greater or lesser time, so that it shall enetrate all parts of the film where light has acted. 1

It is to be understood that the invention is not limited to the use of the particular hydrazin salts and hydf'azids hereinb'efore.

mentioned as other hydrazinsaltsand their fatty derivatives, as well as hydroxylamin salts and their fatty derivatives, for example hydroxylamin phospliite may be used, but excluding the aromatic compounds of hydrazin or hydrox'ylamin, and are to be re garded as equivalents of those mentioned.

shydrazin and hydroxylamin are two bases which may be looked upon as-derived from ammonia (NH,) by the introduction of amido and hydroxyl roups respectively, the salts and the fatty derivatives of these two bases, but excluding the aromatic "com pounds thereof, are hereinafter referred to generically as ammonia derivatives in some of the. claims.

What I claim is As a new article of manufacture, a sensitive photographic surface comprising a vehicle, a hotographic sensitive salt and an ammonia erivative. i

2. As a new article of sitive ver sa manufacture, a senphotographic surface containing a. .sil-

t and an ammonia derivative.

3. As anewarticle of manufacture, a sensitive photographic surface comprising a vehicle, a halogen salt, and an ammonia derivative. f

4. As a new article of manufacture a sensitive photo aphic surface-comprising a colloid vehic e, a halogen salt, and an am-. I

' monia derivative of the kind'set forth. four molecules of silver haloid. In emul'-' 5. a new article of manufacture a sen- 

